Add nim logo to post

.gitignore

 .DS_Store
+
+# When running outside of docker, Hugo writes content here
+/site/public

site/content/post/2018-12-09-over-the-top-optimisations-in-nim.md

 area: optimisation
 ---
 
+<figure class="right">
+  <img src="/res/images/nim/logo.jpg" alt="Yellow crown on a dark background">
+  <figcaption>The Nim logo</figcaption>
+</figure>
+
 For the past few years I've been taking part in
 [Eric Wastl](https://twitter.com/ericwastl)'s
 [Advent of Code](https://adventofcode.com/), a coding challenge that provides